Various diagnostic and medical operations on lumens of the body of a patient, such as the circulation system, the gastrointestinal tract, the brain vessels, the bronchial tree, and the like, are preformed by inserting a catheter through the lumen. Since the catheter is generally a bulky device, it is difficult to guide it to the operational site all on its own. For this purpose, a guidewire whose diameter is substantially smaller than that of the catheter, is inserted to the operational site before inserting the catheter, and then the catheter is passed over the guidewire and guided to the operational site.
Methods and systems for maneuvering the guidewire through the lumen to the operational site, are known in the art. Generally, the operator manipulates the movements of the guidewire, by manually pushing or pulling the guidewire or twisting the guidewire, while he watches an image of the tip of the guidewire, against a real time two-dimensional image of the lumen (e.g., by employing a fluoroscopy angiogram). In this manner, the tip of the guidewire is maneuvered at various bifurcations of the lumens, in order to reach the operational site. The same method is employed for manipulating a catheter, only that a marker (e.g., an X-ray opaque material) is located on the tip of the catheter.
U.S. Pat. No. 6,594,517 B1 issued to Nevo and entitled “Method and Apparatus for Generating Controlled Torques on Objects Particularly Objects Inside a Living Body”, is directed to a system and method for applying a controlled torque on an intra-body device, to bend the tip of the intra-body device. The system includes an input device, a processing and control unit, and electronic-interface, the intra-body device, a torque generating module, a location and direction module and a magnetic resonance imaging system (MRI). The MRI includes a computer, an image display, a gradient activation control unit, an MRI magnet, and a set of three orthogonal gradient coils. The torque generating module includes three micro-coils.
The processing and control unit is connected with the input device, the electronic interface, the computer, and with the gradient activation control unit. The torque generating module and the location and direction module are located at the tip of the intra-body device. The torque generating module and the location and direction module are connected with the electronic interface. The computer is connected with the image display and with the gradient activation control unit. The gradient activation control unit is connected with the orthogonal gradient coils.
The processing and control unit controls the electrical currents through the micro-coils, in order to cause the torque generating module to generate a resultant magnetic dipole to interact with the magnetic field produced by the MRI magnet. This interaction produces a torque of the desired direction and magnitude, in order to steer the tip of the intra-body device. The gradient activation control unit provides the processing and control unit, information respective of the electromagnetic gradient fields generated by the three orthogonal gradient coils, and the timing sequence of the activation of these coils. The image display provides a real time image of the operation field. The location and direction module provides the location and direction or orientation of the tip of the intra-body device. The computer provides the processing and control unit, the event schedule of the MRI system, to prevent image artifacts due to activation of the torque generating module, when the MRI magnets are activated for imaging.
A stereotaxis system is employed for steering a guidewire of a catheter through the lumen, and bending the tip of the guidewire, by applying a magnetic field to the guidewire through a plurality of magnets. Magnetic fields are applied to cause the guidewire to turn in different directions. U.S. Pat. No. 6,035,856 describes such a method.
U.S. Pat. No. 6,035,856 issued to LaFontaine et al., and entitled “Percutaneous Bypass with Branching Vessel”, is directed to a method for performing a bypass on a first occlusion of a branching vessel of the aorta. A coronary artery which includes the first occlusion, and a branching vessel branch out of the aorta. A standard guide-catheter is advanced through the aorta up to the ostium of the branching vessel. An occlusion forming device is advanced through the guide-catheter into the branching vessel, to produce a second occlusion in the branching vessel. The occlusion device includes an elongate portion and a heated balloon.
The occlusion forming device is removed from the aorta through the guide-catheter and a cutting device is advanced through the guide-catheter proximal to the second occlusion. The cutting device includes an elongate member, a steerable guidewire, a proximal occlusion balloon, a distal balloon, a stent, a cutting blade, a first piece of magnetic material and a transmitter. The cutting blade is located distal to the distal balloon, the first piece of the magnetic material is located between the cutting blade and the distal balloon and the transmitter is located within the distal balloon. The distal balloon is located within the stent. The transmitter emits radio frequency signals.
The wall of the branching vessel is cut by employing the cutting blade. The distal balloon is kept in the expanded position, in order to occlude the branching vessel after the branching vessel has been cut. The severed end of the branching vessel is steered toward a region of the coronary artery distal to the first occlusion, by maneuvering the steerable guidewire or by manipulating the first piece of the magnetic material by a second piece of magnetic material, wherein the second piece of magnetic material is located outside the body of the patient.
The true position and the relative position of the transmitter and thus the position of the severed end of the branching vessel, is determined by employing a triangulation and coordinate mapping system. The triangulation and coordinate mapping system includes three reference electrodes which are located outside the body of the patient. Two of the reference electrodes are located on opposite sides of the heart and the third is located on the back. The three reference electrodes are used to triangulate on the transmitter.
When the severed end of the branching vessel is properly positioned, an aperture is formed in the coronary artery distal to the first occlusion, by employing the cutting blade. The severed end of the branching vessel is inserted into the coronary artery through the aperture and the stent is expanded by inflating the distal balloon, thereby attaching the severed end of the branching vessel to the lumen of the coronary artery.